Delta variant is one of the most infectious respiratory diseases known, CDC director says

PUBLISHED: Fri, 23 Jul 2021 08:22:03 GMT
Rich Mendez
Key Points
  • The delta COVID variant is one of the most infectious respiratory diseases seen by experts.
  • Currently, the more infectious strain makes up more than 83% of sequenced cases in the U.S.
  • 97% of people admitted to hospitals with COVID symptoms are unvaccinated.
Rochelle Walensky, director of the U.S. Centers for Disease Control and Prevention (CDC), listens during a Senate Appropriations Subcommittee hearing in Washington, D.C., U.S., on Wednesday, May 19, 2021. Any mandates in the U.S. to require people to be vaccinated against Covid-19 will be set at the local level by companies and institutions such as colleges, the CDC said this week. Photographer: Greg Nash/The Hill/Bloomberg via Getty Images

The delta COVID variant is one of the most infectious respiratory diseases ever seen by scientists, the director of the Centers for Disease Control and Prevention said Thursday.

The variant is highly contagious, largely because people infected with the delta strain can carry up to 1,000 times more virus in their nasal passages than those infected with the original strain, according to new data.

“The delta variant is more aggressive and much more transmissible than previously circulating strains,” CDC Director Dr. Rochelle Walensky told reporters at a briefing Thursday. “It is one of the most infectious respiratory viruses we know of, and that I have seen in my 20-year career.”

Read more: What you need to know about the coronavirus right now

The delta variant has spread quickly through the U.S., accounting for more than 83% of sequenced cases in the U.S. right now, up from 50% the week of July 3.

The seven-day average of new cases is up about 53% from last week, currently at 37,674 new cases per day. Hospitalizations are up 32% from last week at about 3,500 per day and deaths have also increased 19% in the same time frame to about 240 per day.

Chart shows current data on Covid-19 in the United States.
Centers for Disease Control and Prevention

“This virus has no incentive to let up, and it remains in search of the next vulnerable person to infect,” Walensky said.

The virus is ripping through U.S. counties with low vaccination rates, while counties with high vaccination rates are seeing lower rates of new cases.

Three states, Florida, Texas and Missouri, with low vaccination rates accounted for 40% of all new cases nationwide, White House COVID czar Jeff Zients said. Florida alone accounted for 1 in 5 of all new cases in the U.S. for the second week in a row.

Read more: Most fully vaccinated people who get COVID delta infections are asymptomatic, WHO says

In hospitals around the country, 97% of people admitted with COVID symptoms are unvaccinated, and 99.5% of all COVID deaths are also among the unvaccinated.

In the past week, the five states with the highest case counts had higher rates of people getting newly vaccinated compared with the national average.

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